Electric current power-take-off device for enclosed busway systems



D. G. SPRIGINGS L ELECTRIC CURRENT PowER-TAKEmFF DEVICE FOR Jan. 14,1969 ENCLOSED'BUSWAY SYSTEMS Original Fil ed June 30, 1964 SheetINVENTORS UONHLD G. SPRlG H S BY GERHLV EI- Mafia-M3 4 ,fs M 1 mArron/[r Jan. 14, 1969 GSPRIGWGS ET AL 3,422,387

. ELECTRIC CURRENT POWER-TAKE-OFF DEVICE FOR 7 ENCLOSED BUSWAY SYSTEMSOriginal Filed June 30, 1964 Sheet 2 0f 2 H INVENTORE, DOHHLD Gspmsmg BYGERFILO EZMHRTIN ATTORNEY United States Patent 3,422,387 ELECTRICCURRENT POWER-TAKE-OFF DEVICE FOR ENCLOSED BUSWAY SYSTEMS Donald G.Sprigings, Mystic, Conn., and Gerald E. Martin, Lynchburg, Va.,assignors to H. K. Porter Company, Inc., Lynchburg, Va., a corporationof Delaware Original application June 30, 1964, Ser. No. 379,137, nowPatent No. 3,337,697, dated Aug. 22, 1967. Divided and this applicationNov. 7, 1966, Ser. No. 592,386 U.S. Cl. 339-44 4 Claims Int. Cl. Hillr3/06; H011 9/16; H01r 33/12 ABSTRACT OF THE DISCLOSURE This inventionrelates to a power-take-off device or plug for an enclosed busway systemhaving conductor rails at the top of the enclosure, a continuous slot inthe bottom of the enclosure and grounding strips on each side of theslot. The plug has a head wider than the slot, a thickness narrower thanthe slot, a round stern of a diameter equal to the thickness of thehead, an elongated base member on the stern and a web on each side ofthe stem extending from the base and joining the stem. The housingconsisting of these parts is longitudinally split into identical halvesbolted together. Cavities in the head mount contacts spring biasedoutwardly and conductors are connected thereto from a cable extendingthrough the central bore of the stern. Slots on each side of andparallel to the bore in the stem house resilient ground contacts whichextend out of the stem at its juncture with the head. Bent downwardly,the dished ends of the contacts abut the conductive ground strips in thebottom of the busway and urge the plug upwardly, further biasing thepower contacts against the rails. The plug is inserted through the slotin the bottom of the busway and turned 90, during which the groundcontacts cam upward and inward over the bottom of the busway. Notches onthe upper edges of the webs engage with formations on the busway toresist rotation of the plug once it is in its final position.

This application is a division of our pending application, Ser. No.379,137, filed June 30, 1964, now Patent No. 3,337,697, issued Aug. 22,1967.

This invention relates generally to enclosed trolley busway systems inwhich the structural support, protective housing and bus insulation areall combine-d into one thermosetting plastic enclosure, and moreparticularly to an improved construction of a power-take-off plug whichmay be connected into the busway system at any desired point along itslength by insertion upwardly into the busway enclosure through a bottomslot thereof to thereby provide a positionally fixed electrical top-offfor supplying current from said system for operation of a work utility.

The foregoing and other objects of our invention will become clear froma reading of the following specification in conjunction with anexamination of the appended drawings, wherein:

FIGURE 1 illustrates a side elevational view of the enclosed trolleybusway system which is described in detail in our above mentionedcopending application and which description thereof is included hereinby reference thereto;

FIGURE 2 is a vertical sectional view taken through an enclosurecoupling section as would be seen when viewed along the line 22 ofFIGURE 1, the showing of FIGURE 2 being on an enlarged scale;

FIGURE 3 is a view showing the busway enclosure in transverse sectionand the plug-in jack positioned therein "ice for taking off current fromthe current conducting rails, the jack appearing in this figure as anend elevational view thereof; and

FIGURES 4 to 6 are various views of the plug-in jack per se as takenalong the section lines 4-4, 5-5 and 6-6 respectively of FIGURES 3, 4and 5.

In the several figures, like elements are denoted by like referencecharacters.

Referring now to the drawings and more particularly to FIGURES 1 and 2,it will be observed that the trolley of the present invention isdesigned for use in an enclosed trolley busway system including aplurality of longitudinally extending end-to-end alined extrudedenclosure sections 40 secured together by coupling sections 43, all asdescribed more fully in our above-mentioned copending application.

As best seen in FIGURES 2 and 3 the several interconnected enclosuresections 40 which make up the trolley busway system are each generallyrectangular in cross section having an upper wall 45, opposite dependingside walls 46 and a pair of inwardly projecting bottom walls 47separated by a longitudinally centrally extending slot 48 defined by thedown turned spaced apart flanges 49 which form the proximate facingedges of the bottom walls 47. The sidewalls 46 are provided near theirtops with longitudinally extending inwardly projecting ledges orshoulders 46' which face one another and provide physical support forthe conductor rails support blocks hereinafter described. The side walls46 and tOp Wall 45 0f the enclosure sections 40 are cut back at an anglefrom points on the side walls spaced somewhat upward from the bottomwalls 47 so that the interior of the enclosure sections at the endsthereof are accessible from the top and sides. Punched or drilledthrough the side walls 46 proximate the ends thereof are apertures 50 ofproper size, shape and position to have projected thereintocomplementally formed buttons 51 projecting inward from the insidesurface of the side walls 52 of each half of the enclosure sectionscoupling devices 43.

As best seen in FIGURE 2, the side walls 52, top wall sections 53 andinturned bottom walls 54 of the enclosure sections coupling devices 43close fittingly surface engage the top, side and bottom walls of theenclosure section 40 so that the four buttons 51 of each coupling halfproject through the enclosure apertures 50 to interlock the ends ofadjacent enclosure sections when the vertically extending flanges 55 ofthe enclosure coupling halves 43 are fixedly secured together by thenuts and bolts 56 projected through the aligned apertures in saidflanges 55.

Extending longitudinally along and bonded downward upon the uppersurface of the enclosure bottom walls 47 are flat electricallyconductive strips 60 having downturned ends extending below the housingbottom walls 47. As is more particularly shown and described in ourpending application aforesaid, these ends abut one another when twoenclosure sections are interconnected, the abutting ends beingmechanically and electrically connected to one another. The conductivestrips 60 are connected to an electrical ground when the system isplaced in operation and electrically ground the frame of the trolleycollector, as will be subsequently seen, to thereby prevent any shockhazard to personnel utilizing system.

The busway conductor rails 63, as best seen in FIG- URE 2, are ofI-shape in cross section and are slidable endwise longitudinally intoand through grooved formations formed in the conductor support block 65.These grooved formations in the conductor support block are of the samegeneral cross sectional shape as the upper half of the conductor rails63 in that such formations have a horizontally extending open region ofthe same general shape but slightly larger than the upper flange 63a ofthe conductor rails and have a depending vertical slot portion of thesame width as the web 63b of the conductor rails 63. Disposed within theconductor rail flange receiving portion of the grooved formations areresilient biasing strips 66 which hold the conductor rails 63 in stableposition within the support block 65.

The conductor rail support blocks 65 are provided with longitudinallyextending side flanges 65' and a longitudinally extending top rib 67centered between a pair of similarly extending parallel ribs 68-68, thecentral rib 67 extending upward above the surface of the block to agreater extent than the laterally positioned ribs 68-68. The supportblock side flanges 65 seat upon the enclosure side walls shoulders 46whereby the weight of the conductor rails of the system as supported bythe enclosure. As best seen in FIGURE 2, the support block central rib67 projects upward into a groove 69 formed in the underside of theenclosure top wall 45 while the lateral ribs 68 are seated against theundersurface of the enclosure top wall 45. The conductor support block65 is fixedly held in position within the enclosure by a bonding agent70 which securely bonds the support block central rib 67 into theenclosure groove 69 in the enclosure top wall 45.

The enclosure sections 40 may be made of any convenient length as may bethe conductor rails 63, but in general standard lengths will be suchthat enclosure sections and conductor rails will be of the same lengthso that mechanical coupling of the enclosures and electrical splicing ofthe conductor rails may be accomplished at the same point. It is ofcourse understood that the conductor rail splicing is effected beforethe aligned enclosure sections 40 are secured together by the couplingsections 43.

FIGURES 3 to 6 illustrate the plug-in jack structure of the presentinvention which may be connected into the busway system at any desiredpoint by insertion upward through the enclosure bottom slot to provide afixed position electrical tapofl. The plug-in jack unit, designatedgenerally as 146, in generally of T-shaped configuration having a head147 and a stem 148 from the bottom of which latter laterally extends ahandle portion including a flat horizontal flange 149 and a vertical web150 integrally formed with the lower portion of the stem 148 and thehorizontal flange 149.

As best seen in FIGURES 4 to 6, the body of the plugin jack unit isformed of two identical vertically extending halves made of electricalinsulating plastic material and which are secured together by the nutsand bolts 151 projected through the vertical web portions 150 of thejack handle and by the nuts and bolts 152 projected through the headportion 147 of the jack unit. The head 147 of the jack unit is formedwith three vertically extending cavities 153 open at the top and bottom,and with the bottom openings communicating with a horizontally extendingcavity 154 which in turn communicates with the open bottomed bore 155extending vertically through the stem 148 from the bottom thereof.

The top and bottom open ends of the vertical cavities 153 are of smallercross-section than the cavities themselves, the heads 156 of theconductor rails electrical contact elements 157 projecting freely upwardthrough the top openings of the cavities 153 while the flanged portions158 formed at the bottom of the heads 156 extend laterally thereof andare too large to move upward through the cavity top opening and therebyretain the contact elements within the cavities. Extending downward fromthe contact element flanges 158 are stems 159 about which are disposedhelical compression springs 160 which have their upper ends seatedagainst the underside of the flanges 158 and their lower ends seated onthe bottoms of the cavities 153. The springs 160 bias the heads of thecontact elements upward so that the latter are vertically resilientlyshiftable. Electrically secured to and extending downward from thecontact elements 157 into the cavity 154 are electrical conductors 161which are formed into a cable 162 and extended downward through thevertical bore 155 and out of the bottom of the stem 148. The cable andconductors contained therewithin are of course terminated in anyconvenient manner useful for connection to a utility to be operated.

Also formed in the stem 148 and extending vertically parallel to thebore 155 on opposite sides of the latter are a pair of rectangular slots163 which open through the bottom of the stem 148 and turn laterallyoutward in opposite directions at the top of the stem to merge withhorizontally extending open bottomed cavities 164 as formed in thebottom of the head 147. Extending vertically upward through each of therectangular slots 163 from a point below the bottom edge of the stem 148is the vertical leg 165 of a spring metal grounding strip 166, the upperends of the grounding strip vertical legs 165 when turning laterallyoutward into the cavities 164 and merging with angularly laterallyoutwardly extending legs 167 of the grounding strips 166, the outer endsof the downwardly angled legs 167 terminating in upwardly 'dishedcontact cups 168. As best seen in FIGURE 3, the

contact cups 168 are engaged with the enclosure grounding strips 60 whenthe plug-in jack unit 146 is operatively engaged with the busway systemso that the externally accessible lower ends of the vertical legs 165 ofthe grounding strips 166 are at electrical ground potential.

As is best seen in the showing of FIGURE 4, the jack head 147 and stem148 are of the same width, and, as best seen in FIGURE 3, this width isjust slightly less than the width of the enclosure slot between theenclosure lower flanges 49. Moreover, the downward angulation of thegrounding strip legs 167 of the plug-in jack unit is observed to begreater in the showing of FIGURE 5 than in the showing of FIGURE 3. Thisresults from the fact that the distance between the underside of thedished contact cups 168 and the upper surface of the electrical contactelement heads 156 is greater than the vertical distance within theenclosure 40 between the upper surface of the grounding strips 60 andthe under surface of the conductor rails 63.

Consequently, when the plug-in jack is inserted upward into theenclosure 40 through the bottom slot it must be inserted suflicientlyupward to cause the electrical contact elements 157 to engage the centerconductor rail and be depressed downward somewhat into the plug-in jackhead against the bias of the compression springs 160 in order to permitthe dished contact cups 163 of the grounding strips 166 to cam upwardand inward over the enclosure flanges 49 as the plug-in jack unit isrotated through into the position shown in FIGURE 3. Once the contactcups have been cammed up onto the flanges 49 of the enclosure 40, theplug-in jack may be pulled slightly downward by means of the handleflange 149 so that the lower ends of the enclosure flanges may clear theupper edges of the plug-in jack vertical webs and then drop into thereceiving notches 169 recessed downward from the upper edges of thesevertical webs 150.

The engagement of the contact element heads 156 with the conductor rails163 causes the compression springs to tend to drive the entire plug-injack unit 146 downward, but this drive is oflset by the resilient actionof the grounding strips 166 which tend to drive the plug-in jack unitupward by reason of the engagement of the dished contact cups 168 withthe enclosure grounding strips 60. The upward drive of the resilientgrounding strips 166 overbiases the downward drive of the compressionsprings 160 so that the plug-in jack unit moves vertically upward intoits stable position in which the enclosure flanges 49 are seated Withinthe web notches 169, the drive of the compression springs 160 insuring agood contact between the heads of the electrical contact elements andthe above lying conductor rails 63.

Having now described our invention in connection with particularlyillustrated embodiments thereof, it will be appreciated thatmodifications and variations thereof may now occur from time to time tothose persons normally skilled in the art without departing from theessential scope or spirit of our invention, and accordingly it isintended to claim the same broadly as well as specifically as isindicated by the appended claims.

What is claimed to be new and useful is:

1. A current collector plug-in jack device for use in conjunction with aconductor system which includes a plurality of laterally spacedlongitudinally extending conductor rails having downwardly facingcontact surfaces housed within an enclosure having a pair oflongitudinally extending bottom walls defining therebetween a centrallongitudinally extending slot of substantially constant width,comprising in combination,

(a) a main body of insulating material having a head part of atransverse Width greater than and of a thickness less than said slotwhereby said head may be projected upwardly through said slot and thenrotated through 90 degrees to dispose it transversely of said slot andthe conductor rails in said housing, said head part being formed with aplurality of vertical recesses laterally spaced for respective registrywith said rails,

(b) a spring-pressed electrical contact element disposed within each ofsaid recesses and projecting upwardly above the upper surface of saidhead part for resilient engagement with one of the said conductor railswhen said plug-in jack is in operative position within the aforesaidenclosure,

(c) a stem part depending from said head part for projection downwardlythrough said slot and terminating in a handle portion disposedexternally of said housing, said handle portion being adapted tounderlie the bottom walls of said enclosure, and

(d) a pair of spring-pressed elements extending laterally from oppositesides of said stem part in underlying relation to said head part adaptedto resiliently seat upon the bottom walls of the enclosure and therebybias said head part upwardly in said enclosure and effect respectiveengagement of said contact elements with said conductor rails when saidhead part is inserted into and rotated within the enclosure ashereinbefore set forth.

2. A current collector plug-in jack as defined in claim 1 wherein saidhandle portion of the stem part limits upward movement of the jack intosaid enclosure and wherein said handle portion and said enclosure areprovided with coacting interlocking means for preventing unintentionalrotation of the plug relatively to said enclosure upon operative finalengagement of the contact elements with the conductor rails.

3. A current collector plug-in jack as defined in claim 2 wherein saidlaterally extending spring-pressed elements respectively terminate indished extremities which cam over the bottom walls of the enclosure asthe jack is rotated into operative position.

4. A current collector plug-in jack device for use in conjunction withan enclosed conductor system, which system includes enclosure sectionsof hollow generally rectangular cross section formed of electricalinsulation material having a top wall below which are disposed aplurality of side by side parallel extending spaced apart conduetorrails having downwardly facing contact surfaces, a pair of dependingside walls which turn inwardly toward one another at their bottom edgesto form a pair of longitudinally extending bottom walls definingtherebetween a central longitudinally extending slot of substantiallyconstant width, and which bottom walls carry on their upper surfacesconductive grounding strips coextensive with the length of theenclosure, said plug-in jack device comprising in combination,

(a) a generally T-shaped body of insulating material having a head partand a stem part from the bottom of which latter laterally extends ahandle portion including a fiat horizontal flange part and a verticalweb part integrally formed with the lower portion of the stem part, saidhead part being formed with a plurality of laterally spaced verticallyextending cavities each of which opens at the top through the uppersurface of said head,

(b) an electrical contact element disposed within each of said laterallyspaced head cavities and being resiliently upwardly biased by springmeans contained within said cavities so that said electrical contactelements project upward above the upper surface of said head part, eachof said electrical contact elements having electrically connectedthereto an insulated electrical conductor extending downward therefrominto and through said stern part, said electrical contact elements beinglaterally spaced so as to each contact one of the above-lying conductorrails when said plug-in jack is in operative position within theaforesaid enclosure system, and

(c) a pair of spring elements extending laterally from opposite sides ofsaid stem part and underlying the oppositely projecting portions of saidhead part, each of said spring elements terminating in an upwardlydished contact cup, the contact cups of the laterally spaced springelements being separated by a distance approximately equal to thelateral spacing between the longitudinal center lines of the bottomwalls of the said enclosure sections, the spring metal elements of saidplug-in jack and the resilient biasing means associated with theelectrical contact elements of said head part being effective to firmlydrive the plug-in jack electrical head contact elements and spring metalelements into positive engagement respectively with the enclosedconductor rails and the conductive grounding strips in the enclosurebottom walls, said webs which form a part of the aforesaid handleportion of said plug-in jack being provided with means which interfitwith the slit defining bottom wall portions of said enclosure eifectiveto mechanically stabilize said plug-in jack and maintain the same inoperative position within the enclosure.

References Cited UNITED STATES PATENTS 2,279,383 4/1942 Von Gehr 191-232,348,665 5/1944 Von Gehr 339-21 FOREIGN PATENTS 854,276 1/ 1940 France.1,288,609 2/1962 France.

RICHARD E. MOORE, Primary Examiner.

PATRICK A. CLIFFORD, Assistant Examiner.

US. Cl. X.R. 33921, 196

